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BUG: KCSAN: data-race in calc_timer_values / perf_event_update_time

write to 0xffff8880a69358c8 of 8 bytes by task 24088 on cpu 0:
 __perf_update_times kernel/events/core.c:631 [inline]
 perf_event_update_time+0x183/0x200 kernel/events/core.c:638
 perf_event_set_state.part.0+0x4a/0x100 kernel/events/core.c:657
 perf_event_set_state kernel/events/core.c:654 [inline]
 event_sched_out kernel/events/core.c:2116 [inline]
 event_sched_out.isra.0+0x228/0x540 kernel/events/core.c:2088
 group_sched_out.part.0+0x5c/0x140 kernel/events/core.c:2142
 group_sched_out kernel/events/core.c:2137 [inline]
 ctx_sched_out+0x568/0x5a0 kernel/events/core.c:3093
 task_ctx_sched_out+0x59/0x90 kernel/events/core.c:2515
 perf_event_context_sched_out kernel/events/core.c:3279 [inline]
 __perf_event_task_sched_out+0x544/0xb00 kernel/events/core.c:3370
 perf_event_task_sched_out include/linux/perf_event.h:1196 [inline]
 prepare_task_switch kernel/sched/core.c:3158 [inline]
 context_switch kernel/sched/core.c:3337 [inline]
 __schedule+0x3f3/0x690 kernel/sched/core.c:4081
 schedule+0x4a/0x100 kernel/sched/core.c:4155
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x18d/0x290 kernel/futex.c:2704
 futex_wait+0x19b/0x3f0 kernel/futex.c:2810
 do_futex+0xe9/0x18d0 kernel/futex.c:3881
 __do_sys_futex kernel/futex.c:3942 [inline]
 __se_sys_futex kernel/futex.c:3910 [inline]
 __x64_sys_futex+0x2cd/0x3f0 kernel/futex.c:3910
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a69358c8 of 8 bytes by task 24113 on cpu 1:
 __perf_update_times kernel/events/core.c:629 [inline]
 calc_timer_values+0x114/0x1d0 kernel/events/core.c:5429
 perf_event_update_userpage+0x7b/0x340 kernel/events/core.c:5484
 perf_mmap+0xe06/0xf00 kernel/events/core.c:5962
 call_mmap include/linux/fs.h:1907 [inline]
 mmap_region+0x7df/0xd50 mm/mmap.c:1784
 do_mmap+0x6c8/0xba0 mm/mmap.c:1555
 do_mmap_pgoff include/linux/mm.h:2338 [inline]
 vm_mmap_pgoff+0x12d/0x190 mm/util.c:506
 ksys_mmap_pgoff+0x2d8/0x420 mm/mmap.c:1607
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
 __x64_sys_mmap+0x2e/0x40 arch/x86/kernel/sys_x86_64.c:91
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24113 Comm: syz-executor.1 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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